Packaged integrated circuit microelectronic devices are growing in thermal dissipation and heat flux density. Typically containing an integrated circuit substrate made of silicon, silicon carbide (SiC), gallium arsenide (GaAs), indium phosphide (InP), or the like, the integrated circuit substrates have a lower coefficient of thermal expansion (CTE) than typical heat spreader materials such as copper or aluminum. It is desirable to be able to attach these devices to a typical heat spreader made of materials like copper without increased die stress due to CTE and relatively high process temperatures.